Nitrile or Buna N (NBR) Medium Nitrile

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Birmingham Seals is unique in offering a downloadable program which contains our entire catalogue in an easy to install, easy to use program.

Click the button to download the file and please follow the instructions below.

To install simply unzip/uncompress the downloaded file (for Windows XP right-click the file and click on “Extract All…” and follow the on-screen instructions.)

Open the uncompressed folder and run/double-click setup.exe

Temperature Range:  -40°C to + 110°C with excursion to + 135°C

Resistance to mineral based fluids is excellent, although resistance to fuels is not usually good enough. Strength, resistance, abrasion and heat resistance are reasonable. Low-temperature resistance is adequate for most applications but weathering or ozone contact will result in crazing and cracking, particularly under tensile stress or flexure. This grade of nitrile is the most commonly used of all polymers in hydraulic sealing.

Recommended for:-

  1. General purpose sealing
  2. Petroleum Oils and fluids
  3. Cold Water

Not Recommended for:-

  1. Halogenated Hydrocarbons (Carbon Tetrachloride Trichloroethylene)
  2. Nitro Hydrocarbons (Nitrobenzene, Aniline)
  3. Phosphate Ester Hydraulic Fluids (Skydrol, Fyrquel, Pydraul)
  4. Ketones (MEK, Acetone)
  5. Strong Acids
  6. Ozone
  7. Automotive Brake Fluid

High Nitrile

Temperature Range: -30°C to + 110°C

Resistance to mineral based fluids is excellent and to hydrocarbon fuels is good. Strength, Resilience abrasion and high-temperature resistance and reasonable but performance at low temperature is poor. Primarily used in contact with aromatic and mineral oils

Low Nitrile

Temperature Range: -50°C to + 110°C

Low Nitrile has some resistance to mineral based fluids but the main advantage is its low-temperature capability. Strength, resilience and abrasion resistance reasonable.

Note: It is important to remember that all Nitriles are non-resistant to castor based and nonmineral brake fluids and should never be used in applications employing these fluids.

Fluorocarbon Rubber (Viton)

Temperature Range: -20°C to + 200°C

Commonly known as Viton. It is high-temperature capabilities, excellent resistance to hydraulic oils, petrol and many chemicals, including weathering and ozone conditions. Fluorocarbon ‘O’ Rings should be considered for seal use in aircraft, automobile and other mechanical devices requiring maximum resistance to elevated temperature and to many functional fluids

Recommended for use with:-

  1. Petroleum oils
  2. Di ester based lubricants
  3. Silicate ester based lubricants
  4. Silicone fluids and greases
  5. Halogenated Hydrocarbons (Carbons Tetrachloride, Trichoro-Ethylene)
  6. Selected Phosphate ester Fluids
  7. Acids

Not Recommended for use with:-

  1. Ketones
  2. Skydrol fluids
  3. Armines, Anhydrous Ammonia
  4. Hot hydrofluoric or Chlorosulfonic Acids

Silicone Rubber

Temperature Range: -65°C to + 250°C

Silicone has poor tensile strength, tear resistance and abrasion resistance, Silicones possess excellent resistance to temperature extremes. Silicone’s retention of properties at high temperature is superior to other elastic material’s.

Silicones are recommended for:-

  1. Dry Heat
  2. High – aniline point oils
  3. Chlorinated di – phenyls
  4. Food processing applications
  5. Excellent ozone resistance

Silicones are not recommended for:-

  1. Most Petroleum Fluids
  2. Ketones (MEK,Acetone)
  3. Water and Steam


Temperature Range: -60°C to + 180°C

Higher grade of silicone (usually blue) recommended for applications involving hydrocarbon oils, petroleum fuels and mineral based hydraulic fluids. Primarily used for static seals in aerospace fuel systems at temperatures to +180°C. This material experiences similar mechanical limitation to silicone.

Ethylene Propylene Rubber (EPR or EPDM)

Temperature Range: -50°C to + 125°C

Excellent resistance to weathering and ozone, water and steam, with good performance in castor and some phosphate ester based fluids. Its low and high-temperature capability is good, having excellent resistance to set with good resilience.

Boiling water and steam are considered among the most difficult conditions to seal and until the introduction of EPDM around 1961, no adequate elastomeric material was available. This polymer is now used to a large extent in central heating systems replacing the outdated gland material. Also, high-temperature braking systems employing castor based fluids for mouldings subject to weathering and ozone and for seals in chemical plant due to its good chemical resistance.

It should NEVER be used in contact with mineral based fluids or di ester based lubricants, due to excessive swell and deterioration. When lubrication is required, silicone greases or fluids should be used.

P.T.F.E Polytetrafluoethylene

Temperature Range: -200°C to + 250°C

PTFE is an extremely inert material and is unaffected by virtually every known chemical including almost all acids, alkalis and solvents. These exceptional properties make PTFE an ideal material for ‘O’ ring back up rings. It’s cold flow characteristics under permanent strain are usually a disadvantage in PTFE ‘O’ rings e.g. it has little memory to return to its original form.

F.E.P. Encapsulated ‘O’ Rings Viton or Silicone

F.E.P. Viton Temperature Range -20°C to +204°C
F.E.P. Silicone Temperature Range -60°C to + 204°C

An encapsulated ‘O’ ring comprises an elastomer energising core, which has a seamless jacket made from Fluoropolymer. The elastomeric core may be Fluorocarbon (Viton) or Silicone. The jacket is made from Teflon F.E.P. (Fluorinated – ethylene – propylene)

Why are Encapsulated ‘O’ Rings needed?

There are certain applications which prohibit the use of conventional rubber ‘O’ rings. The use of hostile chemicals or extreme temperature (both high and low) during various processes can make effective sealing very difficult. The main advantage encapsulated ‘O’ rings have are solid PTFE is that It has the chemical inertness whilst with its energising core the ‘O’ ring returns to its original form.

Recommended for use in :-

  1. Chemical processing and production
  2. Oil extraction (on shore and off shore)
  3. Petrochemical Refining
  4. Pharmaceutical Production
  5. Food and drink processing
  6. Paint and Dye manufacturing
  7. Cosmetics and Perfumery
  8. Automotive components
  9. Aerospace Engineering

Not Recommended for:-

  1. Dynamic use where high speeds and poor finishes are encountered.
  2. Where the housing design requires excessive stretch or collapse of the ‘O’ ring during installation


Temperature Range -50° C to +315° C

This material has outstanding chemical resistance and a temperature capability up to + 315°C (intermittent) . Wherever rubber components are exposed to aggressive chemicals or high temperatures, Kalrez Perfluoroelastomer parts last longer. Kalrez parts have virtually universal chemical resistance. They are far more resistant to swelling, a key cause of seal failure, and other forms of chemical attack than other elastomers. Kalrez has the chemical inertness of PTFE.